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NAC (N-Acetyl-Cysteine)

Cysteine/NAC (N-acetylcysteine) Information

L-cysteine is a sulfur-bearing amino acid that occurs naturally in protein foods. When used as a supplement, N-acetylcysteine (NAC) is the preferred form of l-cysteine because it is more stable and more easily absorbed. Sufficient amounts of l-cysteine are usually available through the diet in such high protein foods as cottage cheese, yogurt, various meats, granola and wheat germ.

Health Benefits of L-cysteine and NAC

L-cysteine is a precursor to the antioxidant glutathione, which is severely depleted by toxic burdens placed upon the liver by drugs, alcohol, pollution, smoke and industrial chemicals. In a clinical setting, the NAC form of l-cysteine is sometimes used to counteract overdoses of specific substances like acetaminophen.1 L-cysteine is also used by itself and in combination with other nutrients to support more robust hair growth; hair is about 8% cysteine by weight.2

Usage Cysteine and NAC

Use as directed. L-cysteine is available in capsule, tablet and powder form.

Side-effects and Cautions:

Mild gastrointestinal discomfort or rash may occur in some. May cause headaches, especially in those taking nitrates for the treatment of angina. Children or pregnant/nursing women should not take l-cysteine or NAC except under the advice of a physician. l-cysteine or NAC supplements are not recommended for those prone to kidney stones.

1. Toxicology. 2008 Feb 3;244(1):25-34. Epub 2007 Nov 7.
2. J Invest Dermatol. 1993 Jul;101(1 Suppl):56S-59S.